refresh libusual

diff --git a/lib b/lib
index 8d875022f1985eaf8a7080c1b99c811a1c6836b7..5018e6a3c396584f8ecdc187be927bdec1e098f6 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 8d875022f1985eaf8a7080c1b99c811a1c6836b7
+Subproject commit 5018e6a3c396584f8ecdc187be927bdec1e098f6